Baby stroller frame



FIG. 1 is a front perspective view of a baby stroller frame showing my new design, the broken lines are for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a left side elevational view thereof, the right side being identical;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a baby stroller frame, as shown and described. 